A web service broker transforms, at runtime, output data from client applications to the input data form required by various web services. Such transformations are based on data and/or parameter mappings that are accessible to the broker. Further, the broker accesses and invokes particular web services in the manner required by the web services. Such invocations are based on information regarding the access style, such as RPC style of communication, and encoding, such as SOAP, associated with respective web services. The broker provides a generic framework in that it is capable of supporting transformation of different data and data forms from many different applications to respective data that many different respective web services can use.